For a number of years, it is has been a standard part of dental hygiene to remove the calculus on tooth surfaces which can accumulate in the subgingival area. Quite commonly the dental hygienist will use a set of curets to accomplish this task.
One of the standards in the industry for many years has been the Gracey curets. This set of curets was designed by Dr. Clayton H. Gracey in the late 1930's. This comprises a set of curets designed for use in the specific areas of the mouth to make them particularly suitable for subgingival scaling and root planing of periodontal patients. Dr. Gracey's objectives were to design the curets to make it possible to reach into pockets where access is difficult in a manner to properly remove the calculus. The original instruments were designed to be used with a push stroke.
At a later time, there was a modified version to be used with pull strokes. These curets are characterized in that the blade is "offset" and only one cutting edge on each blade is used. Further, the blade is curved in two planes. These curets will be described in more detail later herein, with specific reference to the drawings.
A search of the U.S. Patent literature has disclosed two patents relating to these general types of dental instruments. These are as follows:
U.S. Pat. No. 1,220,933 (Bates) shows what is called a "dental scaler" where the working end of the instrument has a terminal shank portion having in its outer end a cutting blade C which is in the form of a quadrant of a circle, with a rounded cutting tip 1 and two cutting edges 2 and 3 on each side of the concave curved portion of the blade. The lower shank portion which leads into the cutting blade C is positioned at an angle to the lengthwise axis of the handle.
U.S. Pat. No. 4,643,676 (Jansheski) disclosed a dental tool to be used for personal oral hygiene. This comprises a handle having a hooked tip 12 which has a generally triangular cross section. The tipped portion is curved at about 45.degree. to the lengthwise axis of the shank, and the radius of the curvature of the tip 14 is about 0.25 inches. There is a blunted-end tip 16.